Klaus E. Wiemer

A new safe, simple and successful vitrification method for bovine and human blastocysts

This study examined a new method for vitrification of blastocysts that is safe, simple and easy to learn and use. Current vitrification techniques have shortcomings that include the use of dimethyl sulphoxide, one of the more toxic cryoprotectants, and minute containers that are difficult to handle and are usually open to contamination. Cell handling and loading times are very short, which allows no room for user-associated errors and increases the difficulty of the procedure. This study describes a method of vitrification without these shortcomings. Human and bovine blastocysts were exposed to a series of three cryoprotectant solutions and loaded into a 0.25 ml sterile straw, heat sealed at both ends and vitrified. This technique allowed sufficient time for cryoprotectant exposure, loading, sealing and vitrification. Research blastocysts were thawed, cultured for 24 h, and stained for cell viability. The majority survived and on average had few lysed cells. In clinical studies from three different centres, 81.4% of vitrified blastocysts were intact after thawing. Out of 43 transfers with 76 blastocysts replaced, 44.7% implanted, 43.4% yielded a fetal heart beat, and a total of 32 babies have been delivered or are ongoing. The overall clinical pregnancy per transfer rate was 60.4%. The high survival rates and clinical pregnancy rates obtained with this new, safe and easy-to-use vitrification procedure are encouraging.

The combination of coculture and selective assisted hatching: results from their clinical application

OBJECTIVE To establish pregnancies using a combination of coculture and selective assisted hatching. DESIGN Clinical application for a selected group of patients. Not a controlled study. SETTING Private infertility practice. PATIENTS Women with high basal FSH levels, ovulatory disorders, and multiple failed IVF attempts. MAIN OUTCOME MEASURES Pregnancy and implantation rates. RESULTS Of the 95 patients who had coculture and selective assisted hatching, 45 (47.0%) have an ongoing pregnancy with a 23.0% implantation rate. CONCLUSION The combination of coculture and assisted hatching produced acceptable pregnancy and implantation rates within the selected patient population.

Prognostic value of morphologic characteristics of cryopreserved embryos: a study using videocinematography

Fifty embryos, previously frozen at the zygote or 2- to 4-cell stage, were studied. Observers, who were unaware of the occurrence of pregnancy, assessed the morphologic features of these embryos by retrospectively analyzing videocinematographic recordings that were made shortly before replacement. Seven of 26 zygotes and 4 of 24 cleaved embryos implanted, with the incidence of implantation being analyzed in relation to 12 morphologic characteristics. Smooth surface of the blastomeres membranes was a statistically significant predictor of implantation for frozen-cleaved embryos, and variable zona pellucida thickness was the only parameter with predictive value for frozen zygotes. A highly significant difference was found between the implanting capacity of previously frozen-cleaved embryos and the number of abnormal morphologic characteristics. Three quarters of the thawed embryos had at least two abnormal characteristics, indicating that cryodamage was high. Major advantages of videocinematography are the absence of time constraints associated with observing live embryos, the ability to observe new morphologic parameters by freeze-frame and slow motion, and the permanent storage of embryonic data for quality control evaluation.

Embryo number for transfer should not be strictly regulated.

Without question, the rate of multiple gestation resulting from IVF-ET and related assisted reproductive technology (ART) is unacceptably high and must be reduced. One solution to the problem is to enforce laws that require selection and transfer of a predetermined number of embryos after IVF. In fact, this approach has been used in countries such as Germany and the United Kingdom, where, by law, the maximum number of embryos for transfer in any one treatment cycle is three. However, we believe that enforcing these regulations and the rather arbitrary choice of such a number is not only ineffective in significantly reducing multiple pregnancy rates but is also overly simplistic. The preface to the following is this: In the United States, the dilemma at hand is compounded by a health care system that is both competitive and expensive. This system not only discourages any type of regulation, but it often rewards success achieved through extreme measures with which most of us would disagree. Nonetheless, we, as care providers, are a part of this system and must set realistic goals that are attainable within this system. Assisted reproductive technology has many flaws, but let us elaborate on two, which are of particular concern here. One is the inability to select an embryo that is certain to develop to term, thus creating the

Coculture of Human Zygotes on Fetal Bovine Reproductive Tract Cells

When early cleaved human embryos are kept in culture, only one in four can be expected to develop into fully expanded blastocysts.1 Alternatively, only 1% to 12% of them will implant and develop into full-term babies, when replaced into the uterus or fallopian tube before the third cleavage division commences.2,3 Embryonic wastage following assisted reproduction can only in part be explained by an increased incidence of genetic abnormalities or loss at the time of replacement. Other more esoteric factors, like a reduced receptivity of the endometrium in stimulated menstrual cycles, probably play an important role as well.